Do a lot of research and be sure you want to do the work to properly keep discus. They need warm temps of around 82-84 at least, again check this out. Research "plants for a discus tank" and you'll find many you can use BUT depending on the light you use that will determine what plants you can grow so do research on "planted tanks" as well. Discus do much better in planted tanks. Only certain fish like rams, cardinal and rummynose tetras, and sterbai cory cats for example like the warmer temps so research "compatible fish for a discus tank. Substrate should be fine enough to use for plants. Sand or any of the commercial plant substrates. You should do 2 WC's weekly to keep water pristine and do research on a good diet for them. They are messy eaters so be sure to get a good canister filter for the tank.